For starters try different and good quality 16340 batteris and fully charge them
Try the laser with them if that doesn't solve the problem return it for refund or replacement.
You can try fully charging the Etsair batteries but Etsair 16340 3.7V are fraudulently rated junk/scam batteries which claim 2800 mA which is a bad joke and not possible in a battery of that size.---they test out at about 300mA along with other 16340s that claim 2800mA like GLS.
Every battery marketed as Etsair is misrepreseted and a garbage battery.
There are no quality 16340 batteries that are 2800mA ---good quality 16340s run 500 to 800mA or so.